Method for producing a deacidified fluid stream, apparatus for deacidifying a fluid stream and use of heat pumps for deacidifying a fluid stream

A method for producing a deacidified fluid stream from a fluid stream comprising at least one acid gas, comprising:

• a) transferring thermal energy comprising the steps of:
• (i) transferring thermal energy from a heat stream HS1 to a liquid heat transfer material stream HTMS1 of a heat transfer material HTM1 in a heat exchanger HE1 to obtain a liquid heat transfer material stream HTMS2a;
• (ii) expanding the heat transfer medium stream HTMS2a in one or more expansion steps to obtain a gaseous heat transfer material stream HTMS2b (g) having a lower pressure than heat transfer material stream HTMS2a;
• (iii) compressing the heat transfer material stream HTMS2b (g) in one or more compression steps to obtain a gaseous heat transfer material stream HTMS3 having a higher pressure than heat transfer material stream HTMS2b;
• and
• (iv) transferring thermal energy from heat transfer material stream HTMS3 to the regeneration step c) to obtain a heat transfer material stream HTMS4;
• b) contacting a fluid stream FS2 with an absorbent A1 in an absorber to obtain an absorbent A2 laden with acid gases and an at least partly deacidified fluid stream;
• c) regenerating at least a portion of the laden absorbent A2 obtained from step b) in a regenerator to obtain an at least partly regenerated absorbent A3 and a gaseous stream GS comprising least one acid gas;
• d) recycling at least a substream of the regenerated absorbent A3 from step c) into the absorption step b).

An apparatus for deacidifying a fluid stream, comprising

• a) an absorber with
• a. an inlet for fluid stream FS2,
• b. an outlet for a deacidified fluid stream FS3;
• c. an inlet for an absorbent stream A1,
• d. an inlet for regenerated absorbent stream A3;
• and
• e. an outlet for a laden absorbent stream A2,
• b) a regenerator with
• a. an inlet for laden absorbent stream A2;
• b. an outlet for regenerated absorbent stream A3;
• c. an outlet for an acid gas stream GS;
• d. an outlet for absorbent stream AS1, and
• e. an inlet for absorbent stream AS2,
• c) a heat transfer system HP1, comprising a
• a. heat exchanger HE1 with
• a first inlet for a heat stream HS1 and an outlet for a heat stream HS2, and
• a second inlet for heat transfer medium stream HTMS1 essentially consisting of heat transfer material HTM and a second outlet for heat transfer medium stream HTMS2a;
• b. a means for expanding heat transfer material stream HTMS2a to obtain a gaseous heat transfer material stream HTMS2b (g) having a reduced pressure than heat transfer material stream HTMS2a,
• c. one or more compressors connected in series, where the inlet of the first compressor is connected to the second outlet for heat transfer medium stream HTMS2b (g) and the outlet of the last of the series of compressors has an outlet for compressed heat transfer medium stream HTMS3;
• d. a heat exchanger HE-R with
• a first inlet for heat transfer medium stream HTMS3 and an outlet for heat transfer medium stream HTMS4, and
• a second inlet for an absorbent stream AS1 and a second outlet for absorbent stream AS2.